For anyone who's in the early stages and about to do the first online computer test - I could not find much info before I did mine, so here is my experience.
You are given a string of either numbers or letters. You are also given a list of five similar strings. for example:
AGRHULSR
and
AGRHUHSR
GARHULSR
AGRHULRS
AGRHUSLR
AGRHULSR
You have to select the matching string from the list.
There is only one correct answer for each go.
There are 5 rounds of 5 "questions" each.
On the first round you get 9 seconds per question.
This reduces to 5 seconds on the 5th round.
You get to practise as much as you like before you go "live", although I think the practise test had the same questions each time I did it. I recommend experimenting with screen resolution before you go live. Make sure you can read the questions quickly and comfortably as speed is important. Hope this helps quell some fears! I'm still waiting for my results.
Alpha